For centuries, the windmill has been the basic unit for converting wind energy into other forms of energy needed to accomplish useful work. In recent years, significant amounts of money and design effort have been spent to improve the efficiency and economy of wind conversion units. Generally, the result has been the development of large, nonportable devices which require relatively high wind speeds for the economical conversion of wind energy to other forms of energy.
Little attention has been given to the development of moderately sized wind conversion units designed for portability and easy assembly and disassembly. Such units should be light weight and compact for storage and to facilitate mobility, and should be sized for use in isolated locations or mobile facilities. In smaller sizes, the wind conversion unit should be suitable for science demonstration kits or toys.
To effectively drive a moderate to small sized wind conversion unit, it is necessary to maximize the effect of an airstream on the unit, as the air driven blades for the unit will have a limited surface area. In large fluid operated rotors, wind directed against one rotor has been redirected to provide additive torque to a rotor. U.S. Pat. No. 4,005,947 to Norton et al. shows a device of this type where wind is used to exert a forward pressure on one side of a rotor and a reverse pressure on the opposite side. However, if the size of the Norton et al. device was significantly reduced, the wind effect creating the reverse pressure on the opposite side of the rotor would be reduced and much less effective since the volume and speed would drop with the reduction in size.